Background: Pediatric ulnar aneurysms are rare and, unlike their adult counterparts, cannot be explained by repetitive trauma to the palm. A small number of case reports describe diagnostic difficulty with these lesions and different treatments. Methods: We present the case of a 6-month-old with an ulnar artery aneurysm of unknown cause. The diagnosis was supported with magnetic resonance imaging, and the lesion was resected. Results: Because the hand remained well perfused, the ulnar artery was not reconstructed. Conclusions: Although the early result was good, the long-term outcome of this approach is unknown.
